Swift Skateboards sells unassembled skateboards for $65 each. Variable production costs for each board are $10 and fixed production costs are $18. Swift is considering selling the skateboards fully assembled for $72 each. It estimates variable costs for assembling one board will be $3 and fixed costs will be $7. In order for the assembled boards to be more profitable than the unassembled boards, Swift must either

A : increase the sale price of the assembled boards by at least $3 or decrease the fixed costs of assembling the boards by at least $7.

B : increase the sale price of the assembled boards by at least $7 or decrease the variable costs of assembling the boards by at least $3.

C : increase the sale price of the assembled boards by at least $3 or decrease the costs of assembling the boards by at least $3.

D : increase the sale price of the assembled boards by at least $7 or decrease the fixed costs of assembling the boards by at least $7.